EGFR (epidermal growth factor receptor) is a member of the erbB receptor family, which includes transmembrane protein tyrosine kinase receptors. By binding to its ligand, such as epidermal growth factor (EGF), EGFR can form a homodimer on the cell membrane or form a heterodimer with other receptors in the family, such as erbB2, erbB3, or erbB4. The formation of these dimers can cause the phosphorylation of key tyrosine residues in EGFR cells, thereby activating a number of downstream signaling pathways in cells. These intracellular signaling pathways play an important role in cell proliferation, survival and anti-apoptosis. Disorders of EGFR signal transduction pathways, including increased expression of ligands or receptors, EGFR gene amplification and mutation and the like, can promote malignant transformation of cells, and play an important role in tumor cell proliferation, or invasion, metastasis and angiogenesis. Therefore, EGFR is a reasonable target for the development of anticancer drugs.
Therefore, Jiangsu Hansoh Pharmaceutical Group Co., Ltd. developed a small molecule EGFR inhibitor in the patent application PCT/CN2015/091189 (a compound of formula I, the chemical name is: N-(5-((4-(1-cyclopropyl-1H-indol-3-yl)pyrimidin-2-yl)amino)-2-((2-(dimethylamino)ethyl)(methyl) amino)-4-methoxyphenyl)acrylamide), which has the following structure:

This small molecule EGFR inhibitor has high selectivity for inhibiting the EGFR T790M mutant, and has no or low activity to wild-type EGFR. Due to this high selectivity, the skin and gastrointestinal damage caused by inhibition of wild-type EGFR can be greatly reduced, and the drug-resistant tumor caused by the secondary mutation of EGFR-T790M can be treated. In addition, it makes sense to maintain the inhibitory activity to EGFR-activated mutant (including EGFR-L858R and delE746_A750 with exon 19 deletion). Due to the higher selectivity and safety of this small molecule EGFR inhibitor, it is expected to be developed into a clinical first-line therapeutic drug.